1. Field of the Invention
The object of the invention is a method for modernizing an elevator, which elevator is preferably an elevator applicable to the transporting of passengers and/or of freight.
2. Description of Background Art
The original old elevators in old buildings are conventionally often traction sheave elevators provided with counterweights, in which the suspension ratio is normally 1:1, and which comprise a geared hoisting machine that is disposed in a machine room above the elevator hoistway. When old elevators are modernized, the parts of them are replaced for new ones and possibly the rope suspension is changed. The hoisting machine is generally changed for a gearless one, because a gearless machine is cheaper and smaller in size than a geared machine. When a new gearless hoisting machine is installed into an old elevator, also a 1:1 suspension ratio must generally be changed to a 2:1 suspension ratio. In this case, a problem arises from the need to pierce new rope apertures in the floor of the machine room, because a 2:1 suspension needs rope apertures in different places than a 1:1 suspension. Piercing new rope apertures is per se easy, but if this is done the strength of the machine room floor weakens owing to the rather large new rope apertures needed for many parallel ropes. In this case the strength of the floor does not necessarily meet the required safety criteria. In the worst case, the floor of the machine room will no longer endure the weight of the hoisting machine and of the other parts in the machine room, in which case the floor will collapse, which results at least in physical damage and possibly also in personal injury. Owing to this safety risk, it is usually necessary in connection with a change in the suspension ratio to support the hoisting machine on the walls of the elevator hoistway e.g. with steel beams fitted under the floor of the machine room. That being the case, a change in the suspension ratio is in practice generally expensive and is a large operation, and in many cases is rather difficult to implement. One solution presented in publication FI20070994 is that the ropes that ascend from the elevator car are led into the machine room via small holes formed for them. In this solution also holes are made in the floor of the machine room. Likewise in the solution the fixing and positioning of the rope clamps into their positions in relation to each other is not always fast. The placement of the rope clamps into their position one at a time so that they are correctly positioned in relation to each other can be awkward particularly because determining the correct position of the ropes while working in the top part of the elevator hoistway is not easy and, on the other hand, it is difficult to see to the hoistway side from the machine room.